This is a Genuine OE Meyer Plow Pump Fluid Baffle for E Series Pumps 15621. 

Used on Meyer E46, E46H, E47, E47H, E57, E57H, E58H, E68, E78 and E88 Pump Units. 

This mounts on 2 of the tank studs and blocks the fluid from having pressure against the top of the pump while returning to the reservoir. 

Alternate Part Numbers: 15621, 1-M15621